Title :
Measurement of positron range in matter in strong magnetic fields
Author :
Hammer, Bruce E. ; Christensen, Nelson L.
Author_Institution :
Dept. of Radiol., Minnesota Univ., Minneapolis, MN, USA
fDate :
8/1/1995 12:00:00 AM
Abstract :
Positron range is one factor that places a limitation on Positron Emission Tomography (PET) resolution. The distance a positron travels through matter before it annihilates with an electron is a function of its initial energy and the electron density of the medium. A strong magnetic field limits positron range when momentum components are transverse to the field. Measurement of positron range was determined by deconvolving the effects of detector response and radioactivity distribution from the measured annihilation spread function. The annihilation spread function for a 0.5 mm bead of 68Ga was measured with 0.2 and 1.0 mm wide slit collimators. Based on the annihilation spread function FWHM (Full Width at Half Maximum) for a 1.0 mm wide slit the median positron range in tissue equivalent material is 0.87, 0.50, 0.22 mm at 0, 5.0 and 9.4 T, respectively
Keywords :
positron emission tomography; 0 T; 0.2 mm; 0.22 mm; 0.5 mm; 0.87 mm; 1 mm; 5 T; 9.4 T; 68Ga; Full Width at Half Maximum; PET resolution; Positron Emission Tomography resolution; annihilation spread function; annihilation spread function FWHM; detector response; electron density; matter; median positron range; positron range; radioactivity distribution; slit collimators; strong magnetic fields; tissue equivalent material; Biological materials; Electrons; Energy resolution; Magnetic field measurement; Magnetic fields; Magnetic materials; Magnetic resonance; Physics; Positron emission tomography; Radiology;
Journal_Title :
Nuclear Science, IEEE Transactions on
